Cycloidal gearboxes or reducers contain four basic components: a high-speed input shaft, a single or substance cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The input shaft attaches to an eccentric drive member that induces eccentric rotation of the cycloidal cam. In compound reducers, the first an eye on the cycloidal cam lobes engages cam supporters in the casing. Cylindrical cam followers act as teeth on the inner gear, and the number of cam fans Cycloidal gearbox exceeds the amount of cam lobes. The next track of substance cam lobes engages with cam fans on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing quickness.
Compound cycloidal gearboxes provide ratios ranging from as low as 10:1 to 300:1 without stacking stages, as in regular planetary gearboxes. The gearbox’s compound decrease and may be calculated using:
where nhsg = the amount of followers or rollers in the fixed housing and nops = the number for followers or rollers in the slower swiftness output shaft (flange).
There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat treatment, and finishing procedures, cycloidal variations share simple design concepts but generate cycloidal motion in different ways.
Planetary gearboxes are made of three simple force-transmitting elements: a sun gear, three or more satellite or world gears, and an interior ring gear. In a typical gearbox, the sun gear attaches to the input shaft, which is connected to the servomotor. The sun gear transmits motor rotation to the satellites which, subsequently, rotate in the stationary ring equipment. The ring equipment is portion of the gearbox casing. Satellite gears rotate on rigid shafts connected to the planet carrier and cause the planet carrier to rotate and, thus, turn the result shaft. The gearbox provides result shaft higher torque and lower rpm.
Planetary gearboxes generally have solitary or two-gear stages for reduction ratios ranging from 3:1 to 100:1. A third stage could be added for even higher ratios, but it is not common.
The ratio of a planetary gearbox is calculated using the following formula:where nring = the amount of teeth in the internal ring gear and nsun = the number of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should initial consider the precision needed in the application. If backlash and positioning precision are necessary, then cycloidal gearboxes offer the most suitable choice. Removing backlash can also help the servomotor deal with high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do that by optimizing the reflected load/gearbox inertia and speed for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the best torque density, weight, and precision. In fact, not many cycloidal reducers offer ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers can be used. Nevertheless, if the mandatory ratio goes beyond 100:1, cycloidal gearboxes keep advantages because stacking levels is unnecessary, so the gearbox can be shorter and less costly.
Finally, consider size. The majority of manufacturers provide square-framed planetary gearboxes that mate precisely with servomotors. But planetary gearboxes grow in length from solitary to two and three-stage styles as needed gear ratios go from significantly less than 10:1 to between 11:1 and 100:1, and to higher than 100:1, respectively.
Conversely, cycloidal reducers are bigger in diameter for the same torque but are not for as long. The compound decrease cycloidal gear train handles all ratios within the same package deal size, so higher-ratio cycloidal gear boxes become even shorter than planetary variations with the same ratios.
Backlash, ratio, and size provide engineers with a preliminary gearbox selection. But choosing the right gearbox also entails bearing capability, torsional stiffness, shock loads, environmental conditions, duty routine, and life.
From a mechanical perspective, gearboxes have become somewhat of accessories to servomotors. For gearboxes to execute properly and provide engineers with a balance of performance, lifestyle, and value, sizing and selection should be determined from the strain side back to the motor as opposed to the motor out.
Both cycloidal and planetary reducers work in virtually any industry that uses servos or stepper motors. And although both are epicyclical reducers, the variations between most planetary gearboxes stem more from gear geometry and manufacturing procedures instead of principles of operation. But cycloidal reducers are more varied and share small in common with one another. There are advantages in each and engineers should think about the strengths and weaknesses when selecting one over the various other.
Benefits of planetary gearboxes
• High torque density
• Load distribution and posting between planet gears
• Smooth operation
• High efficiency
• Low input inertia
• Low backlash
• Low cost
Benefits of cycloidal gearboxes
• Zero or very-low backlash remains relatively constant during existence of the application
• Rolling rather than sliding contact
• Low wear
• Shock-load capacity
• Torsional stiffness
• Flat, pancake design
• Ratios exceeding 200:1 in a concise size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to employ a gearbox:
Inertia matching. The most typical reason for selecting a gearbox is to control inertia in highly powerful circumstances. Servomotors can only just control up to 10 times their own inertia. But if response time is critical, the engine should control significantly less than four situations its own inertia.
Speed reduction, Servomotors operate more efficiently in higher speeds. Gearboxes help keep motors operating at their optimal speeds.
Torque magnification. Gearboxes offer mechanical advantage by not merely decreasing acceleration but also increasing result torque.
The EP 3000 and our related products that use cycloidal gearing technology deliver the most robust solution in the most compact footprint. The main power train is comprised of an eccentric roller bearing that drives a wheel around a couple of inner pins, keeping the reduction high and the rotational inertia low. The wheel incorporates a curved tooth profile rather than the more traditional involute tooth profile, which eliminates shear forces at any stage of contact. This design introduces compression forces, rather than those shear forces that would exist with an involute gear mesh. That provides several overall performance benefits such as for example high shock load capability (>500% of ranking), minimal friction and use, lower mechanical service elements, among numerous others. The cycloidal style also has a big output shaft bearing span, which gives exceptional overhung load capabilities without requiring any additional expensive components.
Cycloidal advantages over various other styles of gearing;
Capable of handling larger “shock” loads (>500%) of rating in comparison to worm, helical, etc.
High reduction ratios and torque density in a compact dimensional footprint
Exceptional “built-in” overhung load carrying capability
High efficiency (>95%) per reduction stage
Minimal reflected inertia to engine for longer service life
Just ridiculously rugged since all get-out
The entire EP design proves to be extremely durable, and it needs minimal maintenance following installation. The EP is the most reliable reducer in the commercial marketplace, and it is a perfect suit for applications in heavy industry such as oil & gas, primary and secondary steel processing, commercial food production, metal slicing and forming machinery, wastewater treatment, extrusion equipment, among others.